Bolster friction snubbing device



March 8, 1960 E, T, SELEY HOLSTER FRICTION SNUBBING DEVICE Filed DSC. 16, 1957 Zw f7 4 ...li (Ill A TTONEY United States Patent O BOLSTER FRICTON SNUBBING DEVICE Earl T. Seley, Aurora, Ill., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application December 16, 1957, Serial No. 702,989

6 Claims. (Cl. 10S-197) This invention relates generally to railway vehicle trucks and more particularly to trucks wherein the bolster is resiliently supported on the frame for swinging movement with respect thereto.

In the development of railway vehicle trucks it has been found that one type of truck which provides a superior ride is a truck in which the truck frame resiliently supports a bolster which can move vertically on springs with respect thereto and which can also swing or move laterally with the springs tending to restore the bolster to its center position with respect to the truck when displaced laterally. While such swinging movement is considered extremely desirable, unless such movement is snubbed or damped, harmonic oscillations tend to be set up which cause "galloping of the truck. Further, it has been found that as the load on the bolster increases, the magnitude of the lateral and vertical movements of the bolster tend to become greater and consequently require greater damping.

Various devices have been proposed in the past for damping the movements of swinging bolsters under variable loads, such means, however, have required various types of linkages, angularly shaped snubbers, etc., all of which are complicated and expensive and do not necessarily achieve the results desired.

It is an object of the present invention to provide a simple but effective means for damping a swing type bolster on a railway vehicle truck, which damping is in direct relation to the load on the truck bolster. It is a further object of this invention to provide a railway vehicle truck in which the bolster is swingingly supported on air or pneumatic type springs which allow the bolster to move vertically and also swing back and forth laterally. It is still a further object of this invention to provide in a railway vehicle truck in which the bolster is swingingly supported by pneumatic springs, snubbing or damping means which are also pneumatically biased and which bias is reflective of the load on the bolster of the truck.

Ifor a further understanding of the invention and the above and other objects thereof, reference may be had to the detailed description and drawing in which:

Figure 1 is a view of a typical 4-wheel locomotive-type truck in which the bolster is swingingly mounted directly on the truck frame for lateral and vertical movement with respect thereto.

Figure 2 is an enlarged view of a portion of the truck and bolster with parts shown in section and broken away illustrating the details of how the bolster is swingingly mounted and how such swinging movement is uniquely damped.

Referring now to the drawing, a truck indicated generally by a numeral 2 is shown. Truck 2 includes a rigid frame 4 made up of longitudinally extending side frame members 6 secured together in conventional manner by transversely or laterally extending transom members. The truck frame 4 is supported in a conventional manner by means of wheels 8. Wheels 8 are fixed to axles having their ends journalled for rotation in the journal boxes 10 fixed between the pedestal assemblies 12 depending from the side frames 6. Secured to each of the side frames 6 (only one of which is shown since the parts making up the opposite side frame are identical to those of the side frame shown) is a spring seat 14. Seated on each of the spring seats 14 is an air bellows assembly 16. The lower end of each air bellows assembly i6 is secured at its lower end to its seat 14, as for example, by the studs 18. The upper end of each bellows is secured to a flanged cylindrical-like piece 20 by means of nut and bolt assemblies 22. Each cylindrical assembly 20 is welded or otherwise suitably secured to the underside of the bolster 24 of the truck and since it is hollow as indicated at 26 it connects the interior 28 of the bolster with the interiors 30 of the bellows -16.

The bolster 24 as indicated is resiliently supported by the bellows 16 on the truck frame so as to move vertically with respect thereto. The bolster 24 may also move laterally on air springs 16 with respect to the frame. Since the type of truck shown is a driving locomotive truck, movement is transmitted from the truck frame to the bolster by means of longitudinally facing chafing plate assemblies 32 which abut corresponding longitudinally end facing chafing plates 34 provided on the bolster 24. The vehicle body (not shown) which comprises the load on the bolster 24 and consequently the truck 2 is received on the upper part of the bolster in a typical manner, i.e., a king-pin recess is provided on the bolster for receiving a king-pin depending from the underside of the vehicle body. In order that the bolster and accordingly the load carried thereby will remain substantially at the same height from the rails at all times regardless of the load being carried by the bolster, suitable air leveling valves indicated by a numeral 36 have been provided. These leveling valves sense the difference in vertical deflection between the bolster and the frame so that if the deflection is too little these leveling valves will supply increased air pressure to the bellows 16 and the interior 28 of bolster 24 until the deflection is again that which has been selected for operation of the truck. If on the other hand, the load is ,relatively small and the dellection starts to become too great, the leveling valves 36 will sense this variation in deflection and deflate the bellows by relieving pressure therein and in interior 28 of bolster 24 until the deflection again returns to the pre-determined deflection selected for operation of the vehicle. Y It will thus be seen that the bolster 24 tends to remain at a more or less constant height with respect to the frame. Of course, there will be some relative vertical movement of the bolster 24 relative to the frame 4 as the truck is subjected to dynamic loads. In order to clamp this vertical movement and also any lateral movement that might occur between the bolster and the frame, the unique snubbing means indicated generally by a numeral 38 has been provided. This snubbing means comprises a longitudinal center facing cylindrical housing 40 in which is provided a plunger 42. Plunger 42 is maintained in frictional engagement with a longitudinal end facing chafing plate 44. The plunger 42 is loaded by means of a helical coil metal spring 46 and an inflated tire or bellows assembly 4S. This bellows assembly 48 includes a movable stop member 50 to which one peripheral or flanged edge 52 of the bellows 48 is clamped by means of a flanged cupshaped member 54. The bellows or diaphragm 48 fits over the cup part 56 and is sandwiched between the cup member 56 and a second somewhat larger cup member 5S which has a flange 60 provided thereon forming a seat for an end 62 of spring 46. The interior of the diaphragm 48 is connected to the interior 28 of the bolster by means of piping 64 leading to movable stop member 50 and suitable passageways 66, 68 provided in the movable stop member 50 and in the flange of the cupshaped member S4. The movable stop member, including the diaphragm 48 and the cup-shaped members S6, 58, is positioned by means of an internally threaded bushing 79 which is provided with a head 72 xed to the housing 46. Located in the bushing 70 is a screw 74 which may be turned to regulate the pre-load of the spring 46 and plunger 42.

From the foregoing description it may be appreciated that the air under pressure in the interior 2S of bolster 24 is directly transmitted to the interior of the diaphragm 48 and is accordingly applied to the piston or plunger 42. If the load on the bolster should increase either dynamically or statically, such pressure will be directly transmitted to the plunger 42 through the spring 46. ln other words, the greater the loading on the bolster, the greater the pressure in the bolster supporting pneumatic springs 16 and the interior of the bolster and consequently the greater the snubbing or damping'action on the bolster 24. By providing a friction damping snubber of the fluid type and connecting it to the pneumatic bolster springs, a snubbing action is obtained which is directly 'proportional to the loadings of the bolster which is exactly the type of snubbing action desired, since the greater the loading on the bolster, the greater the inertia forces, and the greater the damping must be to snub the movements of the bolster. lf it is not desired to use pneumatic springs for supporting the bolster for swinging movement, it will be appreciated that the leveling valves 36 can be connected directly between the diaphragm 48 and the suitable pressure source provided on the vehicle so that if the deflection increases, greater air pressure will be supplied to the diaphragm 48, or if the deection is less than normal, less air will be supplied to the diaphragm 48. In either event, however, simple means have been provided with are directly proportional to the load on a swinging type of bolster for snubbing movements of the bolster in proportion to the load applied thereto. Further, this snubbing may be adjusted by means of turning of the screw 74 to change the pre-loading of the spring a6.

I claim:

l. A railway truck comprising a frame assembly, a bolster assembly, chargeable air springs for resiliently supporting said bolster assembly on said frame assembly, and means to damp movement of said bolster assembly relative to said frame assembly including a friction plunger supported on one of said assemblies and inflatable expansible means reacting between said plunger and the one of said assemblies and forcing said plunger into frictional engagement with the other of said assemblies.

2. A railway truck comprising a truck frame assembly, a bolster assembly resiliently supported on said frame assembly, and means to damp movement of said bolster assembly relative to said frame assembly including a ver- I tical' surface xed to one of said assemblies, a friction plunger supported on the other of said assemblies and inflatable expansible means reacting on said plunger and the other of said assemblies-forcing it into frictional engagement with said surface.

3. A railway truck comprising a truck frame assembly, a bolster assembly resiliently supported on said frame assembly for movement relative thereto, and means to damp movement of said bolster assembly in accordance with the load thereon including a friction plunger supported on one of said assemblies and resilient inflatable means inflated and deated in response to the vertical deection between said frame and bolster reacting on said plunger and the one of said assemblies and forcing it into frictional engagement with the other of said assemblies.

4. A railway truck comprising a truck frame assembly, a boister assembly resiliently supported on said frame assembly, charged air springs ,on said frame assembly resiliently supporting said bolster assembly thereon for relative movement with respect thereto, said springs being in communication with the interior of said bolster for transfer of air therebetween, a friction plunger supported ou one of said assemblies and resilient inflatable means in communication with the interior of said bolster assembiy for transfer of`air therebetween and reacting on said plunger and the one of said assemblies and forcing it into frictional engagement with the other of said assemblies. Y

5; A railway vehicle truck comprising a frame assembly, a bolster assembly, a charged air spring resiliently supporting said bolster assembly on said frame assembly for movement relative thereto, means responsive to the vertical deflection between said bolster and frame assemblies to vary the charge of said spring, a friction plunger supported on one of said assemblies and in frictional engagement with the other of said assemblies, resilient inatable means `reacting on said plunger and the one of said assemblies and in communication with said spring for transfer of air between said inliatable means and spring, whereby the movement of said bolster assembly relative to said frame assemblies is damped in accordance with the load on said bolster.

6. A railway truck comprising a truck frame assembly, a bolster assembly, an air spring resiliently supporting said bolster assembly on said frame assembly for movement relative thereto, a friction plunger supported on one of said assemblies, a spring and an inflatable diaphragm in series' with each other between said plunger and the one of said assemblies and reacting on said plunger and forcing it into frictional engagement with the other of said assemblies, and means to change the bias of said spring on said plunger.

No references cited. 

